New York City police are searching for a man suspected of sexually assaulting a transgender woman in a bathroom at the historic Stonewall Inn bar in Greenwich Village.

Police said Monday the victim was in the unisex bathroom when the unknown man enters and apparently sexually assaults her. Police say the suspect flees the bathroom, but then returns a short time later and assaults her a second time before leaving.

Police say it happened around 11:40 p.m. Saturday. The victim was treated at an area hospital. There have been no arrests.

Stonewall Inn is the site of 1969 riots that helped give rise to the gay rights movement. Two New York legislators have started a campaign to designate Stonewall Inn as the first national park honoring LGBT history.